PostFader v0.20.0

PostFader v0.20.0

PostFader v0.20.0 is the AI copilot for FL Studio. It connects a local
MCP-compatible AI client to the project already open so it can understand the
session, diagnose exported mixes, work with loaded plug-ins, compose musical
parts, organize patterns and Playlist tracks, and make supported changes.

It starts read-only, never saves the project automatically, and reads supported
direct changes back from FL Studio. Workflows with narrower evidence say so.

This release is published with Windows and macOS setup packages, dedicated
Codex packages, a Claude Desktop extension, Python distributions, the MCP
Registry entry, and SHA-256 checksums.

Which package should I download?

Download the package that matches both your platform and your client:

Package	Best for	What it does
PostFader-v0.20.0-Windows.zip	Windows users and most local MCP hosts	The standard Windows installer and guided setup. Use this for Claude Desktop with the Python setup path, Cursor, OpenCode, T3 Code provider flows, Grok Build, or another local stdio MCP host.
PostFader-v0.20.0-macOS.zip	macOS users and most local MCP hosts	The standard macOS installer and guided setup.
PostFader-v0.20.0-Codex-Windows.zip	Codex on Windows	The Windows installer with Codex configuration preselected and a separate confirmation before codex mcp add registration.
PostFader-v0.20.0-Codex-macOS.zip	Codex on macOS	The macOS installer with the same Codex-specific guided registration.
postfader-fl-studio-mcp-0.20.0.mcpb	Claude Desktop	An optional Claude Desktop extension. Complete the matching platform setup first.
Python wheel or source archive	Advanced users, source installs, and other Python workflows	Install from PyPI or download the wheel/source archive from the release assets, then run postfader setup.

The .mcpb is a Claude Desktop packaging convenience; it does not replace the
platform setup, the matching Universal Bridge, a virtual MIDI endpoint, or FL
Studio MIDI configuration. PostFader does not install or configure virtual MIDI
software. The standard and Codex ZIPs install the same local PostFader server;
the Codex packages add guided Codex registration.

What is new in v0.20.0?

v0.20.0 brings the complete current PostFader production surface:

• Understand the open project. Use 90 tools and 8 live resources to inspect
  mixer routing, Channel Rack generators, loaded effects, patterns, Playlist
  track state, undo/redo history bounds, transport, steps, and exposed plug-in
  parameters.
• Diagnose exported mixes. Mix Doctor translates level, dynamics, tonal,
  stereo, and export-readiness measurements into practical findings. Reference
  comparison, synchronized vocal/instrument masking, persistent peak watches,
  gain-staging plans, and finish assessment support deeper decisions.
• Control the session and loaded plug-ins. Change mixer, routing, transport,
  Channel Rack, pattern, Playlist track, undo/redo navigation, step-sequencer,
  and supported plug-in parameters. Runtime parameter discovery works beyond
  fixed mappings; bundled profiles and a read-only intent resolver connect
  supported goals to known parameter roles for selected FL Studio stock
  effects.
• Create music. Generate deterministic chords, melody, bass, and drums;
  export multi-track Type-1 MIDI and verify the written file; estimate tempo and
  global major/minor key; and transcribe monophonic audio into a reviewable note
  sequence.
• Prepare edits and arrangements. Find and prepare FL-reported empty
  patterns, add section markers, organize Playlist tracks, record supported
  automation values, and prepare Piano Roll append, replace, quantize,
  transpose, humanize, duplicate, delete, or clear operations.
• Get connected faster. Guided setup resolves local paths and the MIDI
  endpoint, deploys the matching bridge, generates client configuration, and
  runs the doctor. Dedicated Codex packages support Windows and macOS.

Writes remain disabled until the user enables them for the current session.
Master changes require explicit permission, supported direct setters use
later-update readback, and an ambiguous mutation outcome is never replayed
automatically.

Upgrade from v0.13

The bridge and server must be upgraded together. Existing v0.13 users should:

1. Close the AI client and FL Studio.
2. Install v0.20.0 and deploy the matching v0.20 Universal Bridge by running
   the guided setup for the selected platform, or by following the
   setup guide.
3. Start FL Studio and reload the Universal Bridge controller script in View
   → Script output. Confirm that the expected ready: MIDI SysEx message
   appears.
4. Regenerate the client configuration, or verify that the existing entry uses
   the v0.20 interpreter, absolute FL Studio user-data directory, exact
   bidirectional MIDI endpoint, and current environment values. Do not run a
   mixed-version client and bridge.
5. Run the doctor and resolve its first corrective action if it does not pass.
6. Before normal use, confirm that the doctor reports overall: "pass",
   bridge_mode: "read_only", verified_writes_enabled: false, and
   runtime_write_mode_control: true.

The .mcpb does not deploy the bridge or configure MIDI, so Claude Desktop
users must complete the same platform setup before opening the extension. Use a
blank or disposable project for the first supervised write test, then disable
writes again when finished.

Qualified environments

The documented v0.20 live qualification matrix passed on the following exact
systems:

Host	Qualified environment
macOS	macOS 27.0 arm64; FL Studio Producer Edition 26.1.3 build 5336; built-in IAC bus.
Windows	Windows 11 x64; FL Studio Producer Edition 26.1.4 build 5589.

The supported range is FL Studio 2026 version 26.1.3 build 5336 or newer with
MIDI scripting API version 44 or newer, Python 3.10 through 3.14, and a local
stdio MCP-compatible client. Python 3.13/3.14 and Windows ARM64 may need a
native compiler for python-rtmidi; the current Windows CI qualification runs
on x64.

At the maintainer-supervised v0.20 qualification revision, the matrix covered
34 authoritative reads, all 8 resources, 39 direct writes, and restoration
checks for every operation. The macOS qualification additionally covered
mixing, real-audio analysis, composition, arrangement, live-note, and manual
Piano Roll apply/transpose/undo workflows. These are qualification results for
the tested revision and systems, not a claim that every FL Studio build,
plug-in, or workstation behaves identically.

Important limitations

PostFader reports control evidence; it does not promise that an action is
reversible or artistically correct. In particular:

• there is no guaranteed rollback and no guaranteed undo point;
• PostFader never saves a project automatically, and it cannot render, export,
  or save a project through the current backend;
• it cannot hear FL Studio's live audio buffer or live output;
• the current backend cannot insert, remove, or reorder plug-ins, and cannot
  reliably control an effect slot's bypass or wet/dry mix;
• some Piano Roll, section-marker, Playlist, and automation workflows have
  narrower evidence. Focus-sensitive Piano Roll dispatch reports preparation
  and key dispatch, not fabricated note readback;
• a write that FL Studio accepts but ignores is reported as unverified, and a
  lost or ambiguous mutation response is not retried automatically;
• plug-in evidence is bounded and product-specific. A write-validated result
  covers a representative control and its restore check, not every parameter,
  option, preset, or audible result; and
• verification proves the observed control state that FL Studio returned, not
  artistic quality or objective creative truth.

The local virtual MIDI endpoint is shared and unauthenticated. Use PostFader on
a trusted, single-user workstation, and use a blank or disposable project
while learning the write workflow. See the security policy
and tool contracts for the full boundaries.

Checksums

The release assets include
PostFader-v0.20.0-SHA256SUMS.txt.
It contains one SHA-256 digest and filename for every downloadable ZIP, MCPB,
wheel, and source archive. Download the checksum file and the artifact from
the same release, then compare the digest before extracting or installing.

If you downloaded every release asset into one directory, run this on macOS or
Linux from that directory:

shasum -a 256 -c PostFader-v0.20.0-SHA256SUMS.txt

If you downloaded only one asset, compare only that asset's digest instead of
running the complete-file check (which will report missing files):

shasum -a 256 PostFader-v0.20.0-macOS.zip
grep '  PostFader-v0.20.0-macOS.zip$' PostFader-v0.20.0-SHA256SUMS.txt

On Windows PowerShell, calculate the artifact directly and compare it with the
matching line in the checksum file:

Get-FileHash .\PostFader-v0.20.0-Windows.z...

Postfader v0.13.0

Postfader V13

Give your AI assistant eyes and carefully checked hands inside FL Studio.
Postfader runs locally, starts read-only, and never saves your project.

Works with your AI client

Postfader is model- and vendor-independent. It works with any MCP-compatible AI
client that can launch a local stdio server, including:

• Claude Desktop and Claude Code
• ChatGPT desktop and OpenAI Codex — desktop app, CLI, and IDE extension
• Cursor — editor and CLI
• T3 Code — through a configured MCP-capable Codex, Claude, or Cursor agent
• Other MCP-compatible desktop and coding assistants

The included helper generates ready-to-use Codex configuration and the standard
mcpServers JSON shape used by Claude-compatible clients. Other MCP clients
use the same executable, arguments, and environment values. The Claude Desktop
.mcpb is an optional convenience package, not a requirement for using
Postfader with another client.

Download and install

🍎 macOS

1. Download Postfader-v0.13.0-macOS.zip.
2. Extract the entire ZIP and quit FL Studio.
3. Double-click Install Postfader.command.
4. Open START HERE - macOS.md and follow the short FL Studio MIDI setup.

If macOS blocks the launcher, Control-click it and choose Open, or run
bash "./Install Postfader.command" from Terminal in the extracted folder.

🪟 Windows

1. Download Postfader-v0.13.0-Windows.zip.
2. Extract the entire ZIP to a writable folder and quit FL Studio.
3. Double-click Install Postfader.cmd.
4. Review the dry-run summary, approve the installation, then open
   START HERE - Windows.md for the FL Studio MIDI setup.

Requirements

• FL Studio 2026 version 26.1.3 build 5336 or newer
• Python 3.10 through 3.14
• Internet access during installation for Python dependencies
• One local virtual MIDI endpoint

Postfader does not install or configure virtual MIDI software. macOS includes
the IAC Driver; Windows users need a bidirectional virtual MIDI endpoint from
the provider of their choice. The included launchers are readable open-source
scripts and are not code signed.

See the complete setup guide for AI-client configuration and troubleshooting.

After installation

1. Enable the same virtual MIDI endpoint under FL Studio's MIDI Input and
   Output, with the same FL Port number on both sides.
2. Set the Input controller type to Universal Bridge and reload the script.
3. Generate configuration for your MCP-compatible AI client using the included
   helper.
4. Start read-only. When you want changes, ask your AI client to enable write
   mode for the current session—FL Studio does not need to restart.

Other downloads

• Claude Desktop extension (.mcpb) — install in Claude Desktop after completing the FL Studio bridge and MIDI setup.
• Python wheel — for Python users who prefer pip.
• Python source distribution.

What’s new in V13

• Windows 11 x64 installer, diagnostics, packaging, and native CI support
• Session write-mode control without restarting FL Studio
• Readback-verified mixer, channel, pattern, transport, routing, and plug-in changes
• Native effect and Channel Rack generator parameter discovery
• Safer exact matching for enumerated plug-in options
• A clearer setup experience and public documentation

Windows FL/virtual-MIDI supervised validation remains pending; the Windows
implementation, installer, native test matrix, clean installs, and release
artifacts are verified in CI.

Verification

• 1,049 safe checks across 21 allowlisted test files
• Clean package installation on macOS and Windows with Python 3.10 and 3.14
• Live macOS read, write/restoration, note, and mid-session mode-toggle acceptance
• Public-tree privacy scan and distribution-content verification

Changes

• Release Postfader v0.13
• Mark Postfader v0.13.0 as stable
• Full changelog

Postfader v0.12.0

What's Changed

• Release Postfader 0.12.0 by @synopsys0 in #1

New Contributors

• @synopsys0 made their first contribution in #1

Full Changelog: v0.11.0...v0.12.0